Over a billion people signed up for Facebook. Half of them in the last year. This site the most used site for people when using the Internet. People are not watching TV anymore - its using Facebook and Youtube and these other web sites. What powerful force draw them to this. Some people denote their time working for others online. What drives people to write an article on Wikipedia? They don´t get paid. Companies are enlisting people to help with innovations and sites such as Galaxy Zoo ask people to help identifying images. And why do people have to film themselves singing and post the video on Youtube? In this lecture we talk about how people are using the web to interact in new ways, and doing stuff.